Keyhole bits keep breaking

Amana Keyhole Router Bit 12″ Diameter x 14″ Shank keyhole slot bit Any tooling gurus out there that know if there are keyhole bits suitable for 12 stock project? Seems like the smallest I've been able to keyhole slot dimensions We use a keyhole bit to cut screw hanging slots in the back of a product we manufacture I recently upgraded my machine from a Stinger to a

keyhole slot hanger This slot should be 27 inches wide After this a tool path can be created with a start depth of 25 ,